Underfloor Insulation Products

Air-Cell Permifloor - our premium under floor product

Three Problems of Uninsulated Floors

Uninsulated timber floors feel cold and are one reason for high energy costs due to insufficient thermal resistance of the floorboards (Floor system R-value R 0.3 - R 0.5)

Drafts through leaky floorboards bring in cold, damp air, pushing warm, heated air up to the ceiling

Moisture rising from the ground diffuses easily through floorboards and most floor coverings, causing condensation problems inside the house. Carpets and matts can become very moist creating the perfect habitat for dust mites to breed

Two Products in One - Air-Cell Permifloor Under-Floor Insulation

When you are going to the trouble of installing underfloor insulation, it pays to install a product that will be working for you for many years into the future. That's why Negawatt has chosen Air-cell as its preferred underfloor insulation product.

Air-Cell consists of a 4 mm thick closed cell foam in between two reflective foils that is installed through stapling to floor joists with overlaps being taped. It comes in 1350mm x 33.33 metre rolls, is very light to handle and will span 2.4 metres unsupported. The tape is a pressure sensitive moisture barrier foil tape, 48mm wide x 50 metres long.

Permifloor is manufactured with a patented closed-cell foam structure sandwiched by highly reflective foil surfaces and perforated with tiny, evenly spaces holes. These perforations allow water and vapour to permeate through preventing moisture that can often collect under flooring with conventional insulation systems.

offers all three functions required for insulating suspended timber floors in one product:

Thermal insulation as a result of 95 % reflection of heat radiation (two reflective foils) and thermal conductivity separation. (en

Draught stop (all joints will be overlapped and airtight taped)

Ground moisture proofing (Vapour barrier)

Negawatt's Air-Cell under-floor insulation combines high performance thermal insulation with a ground moisture proofing vapour and air barrier. Its performance and longevity is unmatched.

Double the Performance of Common Under-floor Insulating Materials with Air-Cell Permifloor

Air-Cell is the most effective and easiest to install under-floor insulating material for suspended timber floors. Installed correctly it will provide double the performance of single perforated builders foils.

The R-value of the floor system insulated with Air-Cell varies between R 2.0 and R 2.3 with a minimum 100 mm air gap, because it depends not only on the thermal properties of the insulation material, but also on factors such as the flooring type, thermal bridges and still air spaces.

Maximum thermal performance depends on creating a still air zone between the flooring and the insulation blanket, which is stapled underneath the floor joists. Thus, all joints and penetrations must be airtight sealed by using Air-Cell pressure-sensitive foil tape. To ensure maximum reflectivity the upper surface of the insulation blanket must be kept clean when installing.

Another advantage of Air-Cell versus other alternatives is that if, after installation, you need to access floor space underneath your home you can simply pull the Air-Cell down and then reattach it. You will not damage the product and you will again achieve 100% performance.

Add about 8% to the actual floor area for overlapping and down-folding. Allow 1 Foil Tape Roll for 2 Air-Cell Insulation Rolls.

Normally you need 2000 staples per house. These are commercial-grade, long-life stainless staples, which will ensure that your Air-cell Permifloor installation is there for the life of the house.

Preparation for Air-Cell DIY - Installation

Air-Cell Permifloor under-floor insulation is safe and easy to install.

Check the under-floor access: Because the insulation is installed from underneath, a minimum height of about 40 cm between the ground and the floor joists is required. Check for the presence of services (e.g. pipes and electrical wires) or other obstructions, which could hinder the work. If you find access difficult, do not hesitate to ask Negawatt for advice.

Calculate the area of your home: Note that when measuring your house you need to allow an extra 8% for overlapping and off-cuts.